The Muellerian Ducts 23 



oviduct, or Fallopian tube, dilated at its anterior end to 

 form the ampulla, or pavilion. The oviduct constitutes a 

 conduit through which the spermatozoa of the male may 

 pass from the vagina and uterus to the ampulla, there to 

 meet and fertilize the freshly discharged ovum. It serves 

 later to transport the ovum, fertilized or unfertilized, to 

 the uterus. The second, or middle portion of the genital 

 tube constitutes the uterine cavity, including the cornua, 

 in which the fetus may find lodgment, attachment, nutri- 

 tion, and protection during its development. The third 

 segment consists of the cervix, which acts as a barrier be- 

 tween the uterus and the vagina. The fourth, or posterior 

 segment — the vagina — extending from the uterus to the 

 vulva, serves first as an essential copulative organ and later 

 as a passage for the fetus at the time of birth. 



The degree of the fusion of the Muellerian ducts and the 

 extent of the specialization of the different areas modify 

 greatly the form and relations of the various segments. 

 The entire genital tube, having a common embryonic origin, 

 has a similar structure, characterized chiefly by three coats 

 — peritoneal, muscular, and mucous. The peritoneal layer, 

 which invests the genital tract almost completely, is derived 

 from the peritoneum of the body wall, behind which the 

 ducts of Mueller originate. At its anterior extremity the 

 genital tract opens, through the pavilion of the oviduct, 

 into the peritoneal cavity. The peritoneum stops at the mar- 

 gin of the pavilion, to be succeeded by the mucous membrane 

 of the oviducts 



The genital tract is supported by the broad ligaments, 

 which consist of two peritoneal layers resulting from the 

 departure of the genital tube from its seat of origin behind 

 the peritoneum. Along the line of their attachment to the 

 genital tube, the peritoneal investment is interrupted to the 

 extent of the area between the two peritoneal folds occupied 

 by the vessels, nerves, pale muscle, and connective tissue 

 fibres constituting the body of the ligament. At the pos- 

 terior extremity of the genital tract, where it opens into 

 the cloaca of the embryo, the peritoneum is reflected upon 



